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Supporters needed to gather 433,971 signatures to place the measure on the ballot. Supporters submitted the last of their signatures Wednesday, bringing their total to nearly 700,000. State officials estimated that 523,531 were valid -- enough to put the 10-page intiative to a November vote.

"We're one step closer to ending cannabis prohibition and the unjust laws that lock people up for cannabis while alcohol is not only old openly but advertised on television to kids every day," Richard Lee, Oakland marijuana entrepreneur and the measure's main advocate, told the LA Times.

The initiative would allow anyone 21 or older to possess, share and transport up to one ounce of marijuana for personal use. It also would allow Californians to grow up to 25 square feet per residence.

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It would be up to local governments to authorize cultivation, transportation and sale. Local governments could then impose taxes.

Supporters say the outcome of the initiative will probably come down to the undecideds -- women in their 30s and 40s with children. They say legalization could save the cash-strapped state about $200 million per year by reducing public safety costs.

Because it would be taxed by local governments, is also could generate revenue. According to an April Field Poll, a slim majority of voters supported legalizing and taxing marijuana to help bridge the state budget deficit.

Opponents have been organizing. They call it a "gateway drug" and claim legalization would persuade more people to give it a try.

"We are quite concerned that by legalizing marijuana, it will definitely lower the perception of risk, and we will see youth use go through the roof," said Aimee Hendle, a spokeswoman for Californians for Drug Free Youth.

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Although California is, once again, at the forefront of a drug issue, it's not alone. In 2012, Nevada might consider state-licensed marijuana stores. In Washington, activists are campaigning for a legalization measure.

California voters approved marijuana for medicinal use in 1996. Fourteen states followed with medicinal marijuana laws of their own.